Rock wool, opportunities for manufacturing in Georgia

GE 0 RG I A GE 0 L 0 GI CAL
G.A.RLllliD PEYTON, Director

S URVEy

425 State Capitol

I

Atlanta, Georgia

{

ROCK- VVOOL
OPPORTUNITIES FOR.. MANUFACTURING
IN
G E 0 R,G I A
BY
A.S.FURCR.ON A.C.J\1\UNYAN
AND
R.. W. SMITH

c . f N t:'O R. MAT I 0 N I R.c u l A R. N 0. I0

N~vEMBER.~ 1939

OPPORTUNITIES FOR BOCK ViJOOL i1J.ANUFACTUTI.E llJ GEORGIA

Rock wool is a heat insulation product which is usually prepared from impure limestone.
No rock wool is manufactured at present in the Southeastern States. Tennessee and Alabama produce sor.1e slag wool, but there are no plants of ..:iny kind manufacturing insulating wool in Georgia, Florida, Louisiana, Mississippi, South Carolina, and North Carolina,. Georgia's geograppic position gives her rare market opport1mities. In the following pages we wish to show that Georgia has a great cpportunity for rock wool mjnufacture; that she has ample rock WJ ol resources; and that costs of plant construction and labor are reasonable in this State.

THE OPPORTUNITY

The market territory for a mineral or rock wool plant in Georgia is probably the states of G-eorgia, North Carolina, South Carolina, Florida, Alabama, Tennessee, Hissi::>sippi, and. possibly Louisiana. At the present time the state of Georgia, North Carolina, and Tennessee ar8 the best markets, South Carolina and Alabama the next best, and Florida the least developed.

~.iuch rock wool, or mineral v:ool~ is being used at present in Georgia
and other Southeastern States. All of this material must be brought in from a Considerable distances SO that the conSU-TJler pays more for his product, yet this additional cost to the consumer does not benefit the manufactu:eer Florida is not favorablir situated for the manufacture of rock wool becaus'e the necessary materials for its manufacture are not easily obtained there, and Florida is far removed from fuels. Atlanta. is one of the best markets in the s outheast and is a city particularly favo~ able to the building trade. This is also true of other large cities, such as Columbus, Rome, Brunswick, Macon, Augu.sta, Savannah, etc. Our warm climate is popolarizing air-conditioning throughout this region. Thus, when we see that no mineral vo ol is manufacturer in other adj ecent states it is obvious that we have an open market for such products in . these states.

Between 1,000 and 1,500 tons of mineral or rock wool are sold yearly

in the Southeast territory outlined above. At the rresent t~~e, this

market is being supplied largely from the states of Indiana, Ohio, New

Jersey, and other states in the Middle West and East. The freight rate

to the Southeast territory amounts to between 12-~% and 17% of the cost

of wool .to the distributors. The leading brands of blowing-wool sell

to the distributors in Atlanta at about ~53.00 p er ton, although a few .

of the "independents" sell it as low as :~35.00 per ton. Batts cost the

distributors 4-~ to 6~ per square f oot.



At the present time, about 60% of the use of mineral vo ol for home
construction in the southeast is in new homes (largely batts), and about
40% in insulating old constru.ction (blowing wool). About 75% of the new '
homes costing ~6,000 and over are being insulated. The saturation point
of insulating -previously constructed homes has by no means been reached,

Page 2
thus the market for mineral wool in the Southeast territory is steadily growing. The greater part of the home insulation in the Southeast is of the ceiling only. The quantity of WDol consumed per house could and should be increased by the use of 2~Lnch batts in the walls, the use for fire-proofing attached garages, and the use under the floors in small but modern homes without a basement. The industrial use of mineral wool could be increased if the manufacturers w-ould put out a l-inch blanket for wrapping air ducts in air-conditioning installations.
The conclusions from numerous intervi6'Ns with companies selling this type of insulation in Atlanta is that a mineral wool plant in Georgia would succeed, provided: (l) It was carefully located in reference to raw materials and distribution facilities; (2) Careful chemical control under an experienced operator is used so as to produce ro ol that is equal in quality to the standard brands in use today. Particular attention should be paid to the quality of the ba.tts, as this use is growing and the installing companies demand batt& that are strong and easy_ to han,dle; (3) The company must be adequately financed so as to be able to st~d the .period of getting their product adopted by the distributors of the Southeast. The few pla.'lts now in the Southeast apparently make a product that does not q1 ite come up to the quality of the "standard brands" and have a very small capacity compared to the present and future market. The freight rate differential of the others offers a decided inducement to locate a progressive mineral wool plant in Georgia.
ROCK VoiOOL RESOURCES
Wool rock, the ordinary source of rock wool, is an impure or siliceous limestone. YJool rocks are recognized by their ehem.ical composition; careful blovdng tests should be made, however, before constructing a plant near a deposit.
Impure limestones or calcareous shales which contain around 40 to
65 per cent calcium carbonate or calcium magnesium carbonate and the
balance, chiefly silica or silica and alumina, vdll make rock mol. Experiments also indicate that rocks which contain between 20 and 30 per cent carbon dioxide will make rock -ro ol. It is obvious from the above remarks that such products as limestone and sandstone, limestone and shale or slate, etc., may be blended to form a suitable mix.
Possibilities for rock l'O ol manufacture occur in many sections of northwest Georgia. From Cartersville and Rome, northward, the Knox dolomite (a cherty dolomite) is a wide-spread formation over this ares. The percentage of silica varies with locality but analyses in our files show that this.formation would be suitable locally for rock vool manufacture. .Another formation common to the area is called the Fort Payne chert~ This fo+-mation ranges from nearly pure chert to a cherty limestone, the latter .locally suitable for rock '\'0 ol .manufacture. These formations and oth,ers of this section have been described and their outcrops have been mapped.
Silurian shales adjacent to the red iron deposits of Dade County contain considerable lime. r,Iany are accessible to the Southern Railway

Page 3.
in Lookout Vall~. Near these shales are outcrops of Mississippian lime$tones, As an example of this type of deposit, excellent outcrops of calcareous shales occur on Shinbone Ridge, east of Trenton.
The following are some typical sections and analyses of wool rock and sub-wool rock in the Paleozoic area of northwest Georgia:
Big Cedar Creek Exposure Floyd Countr Limestone of the Cannas-
~"1fuynard, Poole T., A report on the limestones and cement materials of
north Georgia, Georgia Geol. Surv~ Bulletin 27, pp. 166-167, 1912

auga is exposed over a thickness of about 30 feet about one mile northwest o~ Vans Valley, &ong the north side of Big Cedar Creek. The lower 10 feet of the exposure consists of light bluish-gray limestone resenbling in lithologic character the Knox dolomite; this 1~ feet is wool rock, as illustrated by its analysis below. Immediately above this unit lies 10 feet of cherty limestone Ywhich, in places, might be termed a calcareous shale. Analysis 77 of this unit shows it to be a sub-wool rock. At the top of the exposure, the rock is a dolomitic limestone vh ich resembles the Knox dolomite. It seems likely, therefore, that the entire section might be used in rock w:> ol manufacture.
!nalyses of Limestone from Big Cedar Creek Exposure
77

Lime ( CaO) ....
Magnesia (MgO)
Ferric oxide (Fe2o3)
Sulphur trioxide (s 2o3)
Phosphorus pentoxide (P2o5)
Silica (SiQ2 )
Potash (K2o) A :
Soda (Na20) o~ Clay bases ..... Loss on ignition ~
Carbon dioxide (C02) cal.

tr. .02
.31. 10.. 73 27 ..17 100.00 24.04

14.18 3.20 4.18 tr.
.o4
31.95
4.48
.35 12"68
28.94
100.00
14.62

Page 4.
Cartersville District: Rock wool may be manufactured in and near the Cartersville district - in Bartow and Gorden cotmties north of Cartersville." In that section, both limestone and slate compose the Connasauga formation. The limestoneSrange in chemical composition form high-calcium limestone to dolomite and th~ grade from pure limestone to dolomite through argillaceous limestone to calcareous shale. (The~e rocks ~11 make rock 1m ol. )
There are numberous localities where the limestone is immediately adjacent to the slate. This district has been famous ;for its SLate
quarries for much green slate was quarried in the past. Analyses. of the
slate and the limestones show that the slate waste could be readily combined with the limestone to produ.ce rock .wool; thus the slate could be quarried as a by-product. Although, in recent years, tile and other types of roofing materials have cut into our slate markets, there should be ample sale for this handsome slate for use where dwellings are being constructed at a cost of from twenty to twenty-five thousand dollar&. Indeed, it wou1-d seem that the same salesman might successfully sell both product& at the same time. Railroad an:d highway facilities are excellent in this part of the State. The Louisville and Nashville railroad practically follows the
outcrop of the formation as well as does the new Nat~onal Highway No. 411
from Cartersville to Chatsvvorth. The slates and associated liiaestones are
described in Bulletin 34 of the Geolo.:;ical Survey of Georgia. Description
and analyses may be found in Bulletin 27 of the Georgia Geological Survey, entitled, 11A Report on the Limestones and Cem~nt Hateri.als of North Georgia".
Walker and Dade Counties.: There ar~ many localities :i.n northwest
Georgiavvhere it w'O'UI'd be possible to blend sandstone and limestone in rock
wool manufacture. Carboniferous sandsto_nes a<"ld l.imestones of Lookout Mountain repres ent an example. Lonkout I.::ountain is .capped by thick deposits of sandstone (the Lookout formation and the i'[alden sandstone). These formationS> are underlain by the Bangor limestone. On the .western side of the mountain, the lower portion of the Bangor limestone conta:iiis a considerable amount of chert. The limestone also contains argillaceous and magnesian limestone. In Pigeon Hountain, a spur of Lookout !'!lountain, the Bangor l~~estone has an estimated thickness of 900 ,feet. Here it is directly overlain by the Lookout sandstone and shales.
The coal of Lookout iiountai. n is c~ldng coal. Btrmingham coke may be obtained at reas anable costs . a..'Yl.d natural gas is locally available. T.V.A. power and Georgia power are also available in northvmst Georgia; water power and water are abundant. . Rail:roa.ds and National highways. are rrumerous.
PIEDMOJIIT MARBLE BOLTS: Rock wool could be made from certain rocks in the great belt of crystcl.line rocks v;hich occurs throughdmt middle north Georgia. In Hall and Habersham coU:rit'i:cs, northeast of Atlanta, large deposits of impure marble occur. This marbel belt lies not far from the
Southern Railroad and from the U. s. High~~y 23, through Gainesville,
Baldwin, etc.
, Wool rocks occur in the marble belt of Pickens, Cherokee, Gilmer, and Fannin couties in northern Georgia The Louisville and Nashville
Railroad and State HighTvay No. 5 fallon the belt through Keithsburg,

Page 5.

Sharp Mountain, Ball Ground, Tate, Ellijay, and Blue Ridge. The famous

Georgia marble quarries are located in Tate. Wool rocks probably occur

along this entire marble belt. The following analyses: (GeorgiaGeolog-

ical Survey Bulletin 43! by 1'I. S. Bayley, P 98) show wool rock at Keiths-

burgand at 1"Jhitestone {Llilm.er County):.

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.

ANALYSES OF Blue Gray Marbles from the Keithsburg Belt

Cherokee County, and from Whites.tone, Gilmer

County, Geor,gia



Analyst: Dr. Edgar Everhart '

Keithsburg B~lt

. 1.

2

'Whitestone
3.

Moisture : .o5

.10

Ignition ~ . ..54 .2.p_2,

CaO .. .30.95 . .3.2.6.8. .

.oo
1.18
26.72

]JigO. ; ~ 2.00
F eO . . . . . . . . . . "' 2.03

.81
2.0~

. ... . ' 2.12 .23

l\ffn(j ~ " ~

.oo



Co2.: .......... ..... 25.36 . 2),.36

24.00

.Al203 .... 9.23 . . 1. 0. '..5.8

8.11

Fe2o3 . . . . . . . . . . . .. 3.05 '. 3.86 .
SOJ. . . , Trace _ .00 .

2.65
.oo

P205 .,00 . ,,t~GO . .

.oo

TiO~ . . .38

,3J . .. ... . 1.6.5

Na2o.................... .23 . ol$.. . . .44

.................., .46. . ~21-

.23

,.. I 6 ... t .

................... 26.41. . . _2;1..,37

32.29

o I"' '

~ 100.69' .. '99.9-1 ' - . .. . - . 99.62

' I

Page 6

lt 1. Slightly schistose, fine-gra:ined bluish-gray marble. In stream Crossing road miles southeast of Gover.

2. B~~ish-gray, micaceous schistose marble at qridge over Long Swamp
of Cr~ek, one mile south east of Nelson

3. Vecy fine-gratned, platy gray-blue 'marbie. West side of valley,
south of road leading to Highway No~ _5, 1"1hitestone; G~J.riler. County.

In the following analyses from Sharp Mo1p1tain Creek, in

Cherokee County (Bulletin 43, .P 100), No. &is a: sub-wool rock and

No. 5 is a wool rock:



'



Analyses of Blue-gray Marbles from Sharp Mountain Belt,
Cherokee County, Georgia
Analyst: Dr. Edgar Everhart

4.

5.

Moisture ~ ~ .

;.04

Ignition .--

.10.

CaO .........'........... 20.74

MgO ..................... 2.28

MnO . . .



' FeO ...............'..... 2.11

. co2 (Calculated) .' 17.50

A1 203 . ....,. l6.2J

. . .
'

Fsoe32o3.................................

2.82
.-00

P205 ................' . .oo

TiO2 ..................... .25



N.a20
K2o

.....................
....................

18 .-63

S"i02 '37 .01

Organic Matter.



TOTAL

99.89

.o6
2. 56

'

32.14

1.34


39

25.90

12.13

4.71


.02

.43

.. .' .

.16

.59

19.38
.22

1 0 0. 03

Pege 7

4. Schistose, gray-blue, fine-grained micaceousmarbi~, 2 miles north-
west of Gober, where road_pr.qsses Murphy Creek ....

5. Gray and blue-gray, fine-grai!1ed .- micaceous marble, 2 :mlles west of

Ball Ground on Sharp !Jount<Hn Creek.

.

It should be noted here that marblawas-te.frdtn the quarries
at Tate could be mixed with the sub-vo ol rodcs to form a ru i table product. The combined carbonate content of the marbles qu~ried at I~1arble HUl is
very high, composing 97 to 99 per cen~ of the rock.

APPROXHfATE }iiTNERAL COMPOSITIONS CALCULATED FRm;i' ABOVE ANALYSES FROH KEITHSBURG BTI..T, 'NHITESTONE; AND sHARP MOUNTAIN CREEK BELT

Analysia No.

.. .

1'

2

......................... ... .53.15 53.80 -

Mgco3 .......................... ~ . 3. 76 1.68
Cac()3: Mgco3 .............. 14.1:1 32:1 ~

Soluble constituents other

than earbonatea ....

6.78 3.32

Kaolin ........................... 2.25 11.?5

Epidote 10.35 Feldspars , o o . 4.17
Quartz; .. ~ . 18.44
Excess H2 0 in analysea .oo

16.30 1.56
8. 23
.oo

.4 .

5

34.40 4.53

56.10
2.50

7.5:1 22.5:1

13.70 11.50
4.95 4.91 26.40 .20

8.66 15.20 3.15 4.65 7.86
.03

Granite Waste: The granite operations of DeKalb County, 12 or 15
miles from Atlanta, have accumulated a large a."!lount of fine granite v;aste productd in cutt.ing the stone. It might be possible that this granite waste could be combined "'ith marb~e wast~ from the Georgia marble quarries in the manufacture of rock wool. Should such a combi..n.ation prove feasible, that product could be manufact?red in Atlanta.
Fullers Earth: Vast deposits of calcareous fullers earth, known as the Twiggs clay, occur in south Georgia. These materials are found in Houston, Twiggs, Yvilkins:on, and ~~rashington coun~ie~. The material is a natural wool rock mixture. Jl.iining costs would be low because the material is soft, and, also, because it, could.be mined at the surface by the simplest mechanical equipment. Railroads and highways frequently cross the are of' outcrop; uater and electricity are abundant.

Page 8

A representative s.s:1tple of Twiggs clay from a 10-foot bed of
calcareous fullers earth in Houston County gave us the following analysis:

Al203 ''
Fe203 3.2
s~o2 ........................
CaC0.3 .......................
MgCo3 .._. .................... 6.58
Undetermined 2.78
lOO.o6
co2 (calculated 21.85

The amount of calcium carbonate which this fullers earth contains naturally <varies with the locality.. This is due to the fact that the Twiggs clG.y is a facies of the Ocala limestone. It is possible in this
part of Georgia to find .localities in which the Twiggs clay merges later-
ally into the Ocala limestone. Such localities would undoubtedly be excel-
lent spots for the mining of wool rock.

South Georgia Limestone: The Ocala limestone is quite extensive

in the southwestern portion o.f the State. l;t cov;ers wide .ar.eas. .in Randolph,. . Terrell, Lee, Sumter~ Dougherty, Calhoun, Early, Baker, Miller, Siminole,

and Decatur .counties, :where it outcrops. at t."le surface of the ground. On

its western boundary there are sands and clays and on its eastern edge are

argillaceous limestones. The Ocala is locally quite cherty, but. in oth.er

plac~s it is very Undoubtedly there

rich in calcium carbonate - sometimes are numerous localities in nhich this

as high as 98% Caco3 limestone occurs vrhere

the composit,].on 'WJOUld .be suitable to, the manufacture of rock- V\0 oh

PLANT CONSTRlTCTION AND OPERATION

.

.

It is comparatively simple to make rock wool from sui1ta.ble raw

.materials an~ with adequate heat, but the quality vJill vary- from day to day

unles~ suitable attention is p~id to specifications. The wool rock is

melted in a ~upola-typ!3 furnace; the ~ slag is . then dratm off iN: a thin stream;

falling L~to a high pressure steam, or air blast which disintegrates, or

shears, the. !iquid into l]linute threads. and globules. of. glass which, when ac~

ulated, have the appearance of fluffy wool. Hence, the name, rock wool.

It is an entirely d::ilferent matter, however, to produce a wool in which the siae (diameter an_9. length) of fibers, the percentage of shot (globules), the resiliency, and brittleness must be carefully <;:ontroU~d
to meet specific marketing requirements. There is ample opportunity to improve the ~ulility of rock wool by technical studies. For example, shot Tdl1 be produced when the molten rock stream is attacked by a blast of ste;am~

Page 9.
yet it might be possible to eliminate shot completely by blo~~ng the melt from the cupola through ve~ small -orifices. Constant technical supervision of all plant phase$ in the manufacture is absolutely required in order that a constant product of good quality may be mainta:ined; and, also., in order that the company may keep abreast of the general advancement'in the industry as a Trhole. The last- i tern is quite impoiJtant beaause of the highly competitive nature of the mineral wool business.
J. R. Thoenen of the u. s. Bureau of Hines states that he 11believes
that the manufacture of mineral vrol will continue to be a so-called decentrali~ed industry because of transportation costs and the wide-spread distribution of potential raw materials." Concerning the plants, he says, "they must be highly technical to meet the market demands for specification products. - The manufacture of mineral wool to meet specifications within rapidly narrovring l:L'Llits; is not a simple process and cannot be accomplished without detailed and elaborate technical control." He continues by adding some of the important items which must be considered in plant operations:
"1. Chemical and physical composition of raw materials.
2. Type of melting furnace.
3. Melting and blowing temperature
4. Blowing technique
5. Shot prevention or removal.
6. Consumer's specification requirements. 11
Consequently, it is our recommendation that the services of an experienc~d engineer or technician, trained in the construction of rock wool plants, and their operation, be obtained before proceeding further. Expert advice is extremely advisable. The names of &~ch experts can be
secured from the Uo s. Bureau of Hines, from the manufacturers of rock
wool plant furnaces and machinery, or from present operators of rock wool plants. The Geological Surveys of Illinois, 'Indiana, Ohio, and Kansas; may also be sources of information because those states lead in the manufacture of rock wool.
A detailed description of the many factors entering into the operation and maintenance of a. rock wool plant has been pEepared by J. R.
Thoenen in the u. s. Bureau of Mines Circular 6984R, June, 1939. The
reader is referred to that paper for additi~nal information of this type.
It is likely that arock V\0 ol plant erected in Georgia m uld use the water-jacketed cupol&-tYJle furnace in which to melt the Ymol rock. Also, it is probable that steam under high pressure would be used to blow the wool. S~ch an arrar..gement ;o uld therefore permit the erection of a plant by units - additioLal cupolas being added to the original one as the demand increased. Several advantages are apparent at once in such a set-up.

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Page ll.
Most of the machiner.y used in the plant, excepting the cupola and the packing machines, can generally be assembled from factory equipment manufacturer's suppliesof stock parts. Other pieces of the machinery can be built by a competent mechanic.
Various types of plants, naturally, will range over a wide scala of costs. Therefore, to give the reader some (-idea of what a good plant will cost, figures have been taken from a paper by Charles F. Fryling, chemist, Illinois Geological Surv~, and Orval White, Pr3sident, Mineral Insulation Company, Chicago Ridge, Ill,., read at the Third Mineral Indus-
tries Conference of Illinois, Urbana, 1fuy 18, 1935, and printed in Rock Products Magazine of January, 1936. This paper states that a plant pro-
ducing 1,000 lbs of rock v-o ol per hour should cost approximately ~38,000.
If coke at $4.00 to $5.SO per ton is used, the cost per ton of rock w~ol should be about $2o.oo.
A plant of this size - i.e., one producing 12 tons per d~ - if erected in Georgia, would supply over one-third of the present total consumption of rock v~ol in the southeastern states. Such a figure seems to be a fair one for a local plant.
The construction of a plant for the production of rock vool is not a difficult problem, but the operation of the plant calls for technicals experienced, and capable men provided wvith adequate laboratory equipment for control purposes. The plant should be so designed that it can be operated as units, and constructed as units - addi tional parts being added as increased demands for the product warrant.
A generously financed program for such a business should be the first consideration of any prospective investor. Funds should be provided not only for an efficient plant, but also for a comprehensive sales campaign. That is not to say, however, that the rock wool -producer must have financial backing in excessive proportion to other ventures of similar type, but only to point out thd a quality product depends entirely on adequate plant facilities for turning it out, a~d a sales program for getting it to the consumer.

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